Bradley J. Diak PhD, P.Eng


Mechanical and Materials Engineering, Faculty
Phone: 613-533-3180
Fax: 613-533-6610
Nicol Hall, Room: 328C

Expertise: materials
Bradley J.  Diak
Biography Research Teaching Publications Graduate Students Open Positions

Dr. Diak received both his BASc in Mechanical Engineering and MASc degrees from the University of Manitoba, Canada, and PhD degree in Materials and Metallurgical Engineering from Queen's University, Canada. He conducted post-doctoral research at the Katholieke Universiteit Leuven, Belgium before joining the Department of Mechanical and Materials Engineering in the Faculty of Applied Science (now Smith Engineering) at Queen's University. Dr. Diak's research includes: dynamic measurements of the thermodynamics of plastic flow in metals, alloys, and polymers over large temperature ranges and volumes; studies of solute-defect interactions in metallic solid solutions; control of texture and microstructure development and hence materials properties by processing; developing of new materials characterization methods; and pedagogy in the Materials Science and Engineering discipline. Dr. Diak is a Professional Engineer in Ontario, and a member of ASM, MRS and TMS.

Research Interests 

  • Microstructural Phenomena in Metals and Alloys 
  • Materials for Transportation Applications 
  • X-ray/Electron Scattering Characterization Techniques 
  • Metal Physics Fundamentals

Current Projects 

  • Sculpting Energy Landscapes in Materials: Theory, Experiments and Applications (NSERC)
  • High Temperature Fatigue (CNL/NSERC)
  • Constitutive Modeling of Plasticity (NSERC)

Example Past Projects 

  • Casting and Ageing of Aerospace Alloys (CARIC/CRIAQ/Magellan Aerospace/PWC/Bell Flight) 
  • Structural and Mechanical Behaviour of Dissimilar FSW Al Alloy Joints (Ford USA) 
  • Deformation Response of Oriented Crystalline Aggregates: Experiment and Theory (NSERC) 
  • AUTO21 - Tailor-Welded-Blank Based Mg Alloy Manufacturing for Structural Automotive Parts (Ford/THMg/Auto21) 
  • High Temperature Bond Coatings (Kennametals/Connect Canada) 
  • The Role of Interface Region on Texture Development in Clad Aluminum Sheet Products (Novelis/NSERC) 
  • Micro-indentation studies of the local ductility of Zr-2.5Nb CANDU pressure tubes (NSERC) 
  • Wrought Magnesium for Automobiles - (Timminco/AUTO21 NCE)) 
  • Temperature Dependence of the Rate Sensitivity of Wrought Mg Alloys (CAMM) 
  • Formability Enhancement In Light Weight Structural Materials (GM/NSERC) 
  • Facility to Prototype Designer Crystalline Materials with Preferred Shape and Orientation (CFI)

Symposia & Workshops

The 32nd Canadian Materials Science Conference, Queen's University, June 1-4, 2021.

The Queen's FIB Tool: Introduction for New Users, August 2010

Friday Oct.23, 2009 @ Innovation Park, Queen's University, 945 Princess Street, Kingston, Ontario

Focus: A multi-scale discussion of the progress in understanding how grain boundaries determine polycrystalline plasticity by leaders in the field.

Who will attend? Academics, Graduate Students and Industrial Researchers involved in the field of polycrystalline plasticity*

PROGRAM [Click on titles for abstracts]

08:30h Arrival

08:50h Brad Diak - introduction

09:00h D.J. Lloyd / D. Steele (Novelis)- plasticity effects associated with grain boundaries under bending in a 6000 Al alloy

09:45h Ron Miller (Carleton) - mechanisms and prediction of dislocation nucleation due to stress

10:30h Marc Seefeldt (Catholic University of Leuven)- grain fragmentation and scaling laws

11:15h Brad Diak / Atish Ray (Queen's)- grain interactions and f.c.c. texture stability

12:00 Lunch

13:00h Mark Daymond (Queen's) - length scales for residual stress

13:45h Abhijit Brahme / Kaan Inal / Raj Maishra / Shig Saimoto (Waterloo / Waterloo / GM Warren / Queen's) - The backstress effect of evolving deformation boundaries in f.c.c. polycrystals

14:30h Paul Van Houtte (Catholic University of Leuven)- texture models incorporating strain heterogeneity

15:15h Discussion

16:00h Dismissal

*Due to limited space, participation is unfortunately by invitation only.

For more information please contact Brad Diak (tel:1(613)533-3180 /

Courses as Instructor (Current) 

  • MECH 39X - Mechanical & Materials Engineering Labs
  • MECH 844 - Special Topics (Textures and Microstructures)
  • MECH 878 - Dislocation Theory

Courses as Instructor (Current and Past) 


  • Decoding stress-strain parameters in FCC metals using digital constitutive analyses to devolve dynamic obstcle-strength factor and diffuse necking. S. Saimoto, K. Inal, B.J. Diak, A. Kula, M. Niewzcas, M.R. Langille, Materialia 33 (2024) 102045. online.
  • Not all screens are created equal: examination of surface features and other physical properties of commonly used screen materials for smoking drugs. B.J. Diak, M. Miskovic, N. Zurba, D. Beaumont,  Harm Reduct J 20 (2023) 68. online.
  • Assimilated Model of Work- Hardening in FCC Metals and Its Application to Devolution of Stored Work. S. Saimoto, B.J. Diak, A. Kula, M. Niewczas,  Matls. Today Comm. 34 (2023)105115.
  • Rate-Controlling Microplastic Processes during Plastic Flow in FCC Metals: Origin of the Variation of Strain Rate Sensitivity in Aluminum from 78 to 300 K. S. Saimoto, B.J. Diak, M. Niewczas,   Crystals. 12(12) (2022) 1811. online.
  • Dislocation-obstacle interaction evolution in rate dependent plasticity of AlSi10Mg as-built microstructure by laser powder bed fusion, A. Salandary-Rabori, Bradley J. Diak, Vahid Fallah, Matls. Sci. Eng. A 857 (2022) 144043. on-line.  
  • Advanced method for structure-strength-ductility assessment of dispersion-strengthened FCC metals using activation work, mean slip distance and constitutive relation analyses: Decoding the Haasen plot, S. Saimoto, B.J. Diak, Matls. Sci. Eng. A 828 (2021) 57-65. on-line. 
  • The role of cooling rate in microstructure in a sand-cast Al-Cu-Ag alloy containing high amounts of TiB2, Lucas Ravkov, Bradley Diak, Mark Gallerneault, Peter Clarke, Giuseppe Marzano, Cdn. Met. Quart. 60 (2021) 57-65. e-print. 
  • Forensic Analyses of Microstructure Evolution of Stage II & III: New Assimilated Model for Work-hardening in FCC Metals, Shigeo Saimoto, Bradley J Diak, Anna Kula, Marek Niewczas, Acta Mater. 198 (2020) 168-177  online.  
  • Asymmetry of strain rate sensitivity between up- and down-changes in 6000 series aluminium alloys of varying Si content, MR Langille, BJ Diak, F De Geuser, A Deschamps, G Guiglionda, Materials Science and Engineering A, 788 (2020) 139517 online 
  • High-Resolution Residual Stress Mapping of Mg AZ80 Friction Stir Welds for Three Processing Conditions, Jessica Hiscocks, MR Daymond, BJ Diak, A Gerlich, Metals. and Maters. Trans. A. 51 (2020)  1195-1207 online.  
  • Specific resistivity of dislocations and vacancies for super-pure aluminum at 4.2 K determined in-situ and post-recovery deformation and correlated to flow stress, Shigeo Saimoto, Marek Niewczas, Michael R. Langille, Bradley Diak, Phil. Mag. 99 (2019) .  DOI: 10.1080/14786435.2019.1640404 Taylor Francis Link 
  • Non-isothermal thermal cycle process model of predicting post-weld hardness in friction stir welding of dissimilar age-hardenable aluminum alloys, Olga Gopkalo, Xu Liu, Fei Long, Michael Booth, AP Gerlich, BJ Diak, Matls. Sci. Eng. A754 (2019) 205-215. Elsevier Link 
  • Comparison of the Elastic-Plastic Transition in Nanocrystalline NickelPillars Fabricated by Electron Beam Lithography and Focused Ion BeamMethods, M. Sedore, B.J. Diak, A. Murray, B. Riel, 40th Risø International Symposium on Materials Science: Metal Microstructures in 2D, 3D and 4D, IOP Conference Series-Materials Science and Engineering  vol. 480 (2019) UNSP 012023. Open Source  
  • Rolling texture development in Aluminum-Zinc solid solutions, B.J. Diak, B. Merkley, O. Gopkalo,  18th International Conference of Textures of Materials (ICOTOM-18) IOP Conference Series-Materials Science and Engineering  vol. 375 (2018) UNSP 012024. IOP Link  
  • Re-examining the relation between fracture strain and yield stress in Al-Mg-Si alloys, M.R. Langille, B.J. Diak, S. Saimoto, Matls. Sci. Eng. A705 (2017) 196-199. Elsevier Link 
  • Formation mechanisms of periodic longitudinal microstructure and texture patterns in friction stir welded magnesium AZ80, J. Hiscocks, B.J. Diak, A.P. Gerlich, M.R. Daymond, Matls. Char. 122 (2016) 22-29. Elsevier Link. 
  • Crystal plasticity modeling of damage accumulation in dissimilar Mg alloy bi-crystals under high cycle fatigue, S. Knight, B.J. Diak, M.R. Daymond, Intl. J. Fatigue 90 (2016) 99-108. Elsevier Link. 
  • On the deformation twinning of Mg AZ31B: A three-dimensional synchrotron X-ray diffraction experiment and crystal plasticity finite element model, H. Abdolvand, M. Majkut, J. Oddershede, S. Schmidt, U. Lienert, B.J. Diak, P.J. Withers, M.R. Daymond, Intl. J. Plast. 70 (2015) 77-97. 
  • Application of the Nes Model for Static Recovery of the Dislocation Density in Cold Rolled AA6XXX, A. Penlington, B.J. Diak, H Jin, Matls. Sci. Forum, 794-796 (2014) 605-610. 
  • Fine Pore Structure Characterization in Two Gessoes Using Focused Ion Beam Scanning, Doutre, A. Freeman, B. Diak A. Murray, G. Bevan, L. Fuster-Lope,MRS Proceedings vol. 1656, Symposium PP, Materials Issues in Art and Archeology, ed. by Vandiver, Li, Maines, Sciau, (2014) Cambridge Journals On-line. 
  • Nanovoid characterization of nominally pure aluminium using synchrotron small angle X-ray Scattering (SAXS) methods. 
    A. Chaudhuri, M.A. Singh, B.J. Diak, C. Cuoppolo & A.R. Woll, Phil. Mag. 93 (2013) 4392-4411. 
  • Point defect generation, nano-void formation and growth: I, Validation , S. Saimoto and B.J. Diak. Phil. Mag. 92 (2012) 1890-1914. 
  • Point defect generation, nano-void formation and growth. II. Criterion for ductile failure , S. Saimoto, B.J. Diak, D.J. Lloyd. Phil. Mag. 92 (2012) 1915-1936. 
  • Classification of textures and microstructure stability in rolled f.c.c. metals with grain Interactions , A. Ray and B. J. Diak. Sci. For. 702-703 (2012) 253-260. 
  • Multiscale modelling of the induced plastic anisotropy in bcc metals, C.J. Hamelin, B.J. Diak, A.K. PilkeyIntl. J. Plast. 27 (2011) 1185-1202. 
  • Grain interaction effect on the stability of the {110}<112> "brass" orientation in an aluminum multi-crystal, Atish Ray, B.J. Diak, Scripta Mater. 62 (2010) 606-609. 
  • Dynamic measurement of thermally activated flow in dilute Al-xMn solid Solutions: Experiments and Modelling, Bradley J. Diak, Bjorn Holmedal, Eric Nes, Plasticity 2010, A.S. Khan and B. Farrokh (eds.), NEAT Press (2010) 88-90. 
  • Recovery Studies of Cold-rolled Aluminum Sheet Using X-ray Line Broadening and Activation Volume Determinations, S. Saimoto, J.I. Cooley, B.J. Diak, Hiaou Jin, R.K. Mishra, Acta Mater. 57 (2009) 4822-4834. 
  • Effects of Heat Treatment on Microstructure and Tensile Deformation of Mg AZ80 Alloy at Room Temperature. I.A. Yakubtsov, B.J. Diak, C.A. Sager, B. Bhattacharya, W.D. MacDonald and M. Niewczas, Mat. Sci. Eng. A, 496 (2008) 247-255. 
  • Early Stage Decomposition of AA6111: II. Small Angle X-ray Scattering, Aluminium: Their Physical and Mechanical Properties. B.J. Diak M.A. Singh, L.A. Westfall and S. Saimoto, ed. by J. Hirsch. B. Skrotzki, G. Gottstein, Wiley-VCH (2008) 822-827.
  • Stability of Cube Orientation in Aluminum Under Plane Strain Compression: a Grain-Grain Interaction Perspective. Atish Ray and B.J Diak, Aluminium: Their Physical and Mechanical Properties, ed. by J. Hirsch. B. Skrotzki, G. Gottstein , Wiley-VCH (2008) 1097-1102.
  • Modeling and Simulation of Mg AZ80 Alloy Forging Behaviour. F. Ju, X. Zihui, B.J. Diak, O.A. Ojo, W.D. MacDonald, M. Niewczas, SAE International, SP-2205, Magnesium Technologies (2008) 23-32.
  • Dynamic Dislocation Analysis and SAXS Study of Nano-void Formation in Aluminum Alloys, L. Westfall, B.J. Diak, M.A. Singh and S. Saimoto, ASME Journal of Materials and Technology 130 (2008) 021011.
  • Quantitative Characterization of the Microstructure of Bainitic Linepipe Steels,D. Boyd, I. Yakubstov, B. Diak, Proc. Intl. Conference on Microalloyed Steels, AIST (2007) PR-293-008. 
  • Strength by Chocolate, B.J. Diak, Int. J. Engng. Ed., 22 (2006) 925-936. 
  • Recovery of Tensile Properties of AA5182 after Cold Rolling, B.J. Diak and B. Verlinden, Matls. Sci. Forum, 519-521 (2006) 1653-1658. 
  • Origin of the Depth Dependence of the Apparent Activation Volume in Polycrystalline 99.999Cu Determined by Displacement Rate Change Micro-indentation, R.J. Klassen, B.J. Diak and S. Saimoto, Mat. Sci. Eng. A387-389 (2004) 297-301. 
  • Designer Crystalline Aggregates: A proposed tool to evaluate the role of grain-grain interactions on evolution of deformation textures and microstructures, B.J. Diak, A. Ray, E.M. Griswold and M.W. Phaneuf, in 25th Risø International. Symposium on Matls. Sci.: Evolution of Deformation Microstructures in 3D eds. Gundlach et al., Risø National Laboratory, Roskilde, Denmark (2004) 283-289. 
  • A Constitutive Description of the Hot Working of AA1050 Using the Mean Slip Distance as a Structure Parameter, B.J. Diak and B. Verlinden, in Hugh McQueen Symposium, Light Metals 2002, ed. By T. Lewis, Met. Soc. CIM (2002) 881-898. 
  • Strain Rate Sensitivity of Ultra-Low Carbon Steels, S. Saimoto and B.J. Diak, Mat. Sci. Eng. A322 (2002) 228-232. 
  • Assessment of Decomposition Products in an Al-Mg-Si Alloy by Instrumented Micro-indentation, B.J. Diak and S. Saimoto, Mat. Sci. Eng. A319-321 (2001) 909-913. 
  • The Possible Role of Point Defects During Plastic Deformation of IF Steel, S. Saimoto and B.J. Diak, Mat. Sci. Eng. A319-321 (2001) 294-298. 
  • Materials Characterization of Plastic products by Thermodynamic Response using Micro-indentation, S. Saimoto and B.J. Diak, in 4th Pacific Rim International Conference on Advanced Materials and Processing, eds. S. Hanada, Z. Zhou, S.M. Nam and R.N. Wright, Japan Institute of Metals, 2001, pp. 1932-1926. 
  • The Determination of Evolving Microstructure Using Constitutive Relationships, B.J. Diak and S. Saimoto, in Multiscale Phenomena in Materials - Experiments and Modeling: MRS Symposium, vol. 578, eds. I.M. Robertson, D.H. Lassila, B. Devincre and R. Philips, MRS Publications, 2000, pp.45-50. 
  • Evaluation of Phase Decomposition and Precipitation in an Al-Mg2Si Alloy by Quantitative Measurement of Dislocation-Defect Interactions, B.J. Diak and S. Saimoto, in Solid-Solid Phase Transformations '99, Kyoto, Japan, JIM, 1999, pp.125-128. 
  • Continuous Recrystallization Characteristics in Metal Systems, S. Saimoto, Haiou Jin and B.J. Diak, in Fourth International Conference on Recrystallization and Related Phenomenon, eds. T. Sakai and H.G. Suzuki, JIM, 1999, pp.781-786. 
  • Characteriation of clustering in IF steels by thermodynamic response measurements, S. Saimoto, J.N.A. Starling and B.J. Diak, JIM, Proc., Vol 12, (JIMIC-3), Pts. 1 and 2: Solid - Solid Phase Transformations, 1999, pp.1557-1560. 
  • Role of the Deforming Volume on Plastic Flow as Examined by Micro-Indentation, B.J. Diak and S. Saimoto, in Plasticity '99: Constitutive and Damage Modeling of Inelastic Deformation and Phase Transformation, ed. A.S. Khan, Neat Press, Fulton, Maryland, 1998, pp.561-564. 
  • Characterization of Thermodynamic Response by Materials Testing, B.J. Diak, K.R. Upadhyaya and S. Saimoto, Progress Mat. Sci., 43 (1998) 223-363. 
  • Micro-indentation Using Strain Rate Sensitivity to Examine Deformation of Polymeric and Metallic Surface Layers, W.R. Newson, B.J. Diak and S. Saimoto, in Thin Films: Stresses and Mechanical Properties, VI, MRS Symposium, vol. 436, eds. W.W. Gerberich, H. Gao, J.-E. Sundgren and S.P. Baker, MRS Publications, 1997, pp.359-364. 
  • Formation of Cube Texture in Nominally Pure Aluminum with Fine Particle Dispersion, S. Saimoto, J. Li, G. Langelaan, B.J. Diak and J. Shimuzu, Textures and Microstructures 26-27 (1996), 245-262. 
  • Characterization of Tempering Behaviour of Fe-2.25Cr-1Mo Using Strain Rate Sensitivity, B.J. Diak, K. Harold and S. Saimoto, 1st Intl. Conf. Microstructures Mech. Properties of Aging Materials, Liaw et al. (eds.), Chicago, IL, Nov. 02-05, 1992, publ. TAIME/TMS (1993) pp.117-122. 

Research Group Members 




Dylan Broad 

MASc Candidate 
High Temperature Creep 

Marjan Moradi

PhD Candidate 
Energy Landscapes in Crystalline Materials


Past Members 

Anne Kupecz; Steve Ancic; Chris Sager; Rathna Lanerolle; Igor Yakubtsov; Colleen Decker; Luke Westfall; Liz Lauzon; Isaac Gordezky; Cory Hamelin; Atish Ray, Joyce Cooley; Chris Gabryel; Chris Cuoppolo; Debartha Bag; Arnab Chaudhuri; Bob Noakes; Marta Majkut; Alex Penlington; Adam Brooks; Nicola McFadden; Dalton Kellett; Kshitij Sinha; Simon Knight; Brad Merkley; Xu Liu; Nick Cottee; Matthew Sedore; Michael Cain; Jessica Generosa, Devon Gilbert, Michel Haché;  Jessica Hiscocks; Eric Sammut; Desmond Williams; Kodie Becker; Noemie Sauvage; Michael Langille; Lucas Ravkov; Melissa Young; Rosen Ivanov; Olga Gopkalo; Sean Farrell; Alek Pach; Yvonne Anabaranze; Megan Tucker.

Positions Available*

  • MASc Student, Deformation mechanisms in hard media used by mining industries.  Joint Mining/Mechanical and Materials project (Apply by April 30 with Sept. 1, 2024 start)
  • PDF & PhD, Modeling, processing and characterization of microstructure in rapidly cooled aluminum alloy plates for structural or electrical applications (Open for Sept. 1, 2024 start)
  • PhD Student, Origin of surface patterning and instabilities in crystalline solids (Open, but pending funding)
  • PhD Student, Study of proton beam energy rate on irradiation path dependence (FILLED)

* Please email (i) cover letter expressing your interest and experience that makes you ideal for the specific position, (ii) resume or C.V., and (iii) list of personal references.

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